/*M///////////////////////////////////////////////////////////////////////////////////////
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//                           License Agreement
//                For Open Source Computer Vision Library
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#include "precomp.hpp"
#include "grfmt_bmp.hpp"

namespace cv {

static const char* fmtSignBmp = "BM";

/************************ BMP decoder *****************************/

BmpDecoder::BmpDecoder() {
    m_signature = fmtSignBmp;
    m_offset = -1;
    m_buf_supported = true;
}


BmpDecoder::~BmpDecoder() {
}


void  BmpDecoder::close() {
    m_strm.close();
}

ImageDecoder BmpDecoder::newDecoder() const {
    return new BmpDecoder;
}

bool  BmpDecoder::readHeader() {
    bool result = false;
    bool iscolor = false;

    if (!m_buf.empty()) {
        if (!m_strm.open(m_buf)) {
            return false;
        }
    } else if (!m_strm.open(m_filename)) {
        return false;
    }

    try {
        m_strm.skip(10);
        m_offset = m_strm.getDWord();

        int  size = m_strm.getDWord();

        if (size >= 36) {
            m_width  = m_strm.getDWord();
            m_height = m_strm.getDWord();
            m_bpp    = m_strm.getDWord() >> 16;
            m_rle_code = (BmpCompression)m_strm.getDWord();
            m_strm.skip(12);
            int clrused = m_strm.getDWord();
            m_strm.skip(size - 36);

            if (m_width > 0 && m_height > 0 &&
                    (((m_bpp == 1 || m_bpp == 4 || m_bpp == 8 ||
                       m_bpp == 24 || m_bpp == 32) && m_rle_code == BMP_RGB) ||
                     (m_bpp == 16 && (m_rle_code == BMP_RGB || m_rle_code == BMP_BITFIELDS)) ||
                     (m_bpp == 4 && m_rle_code == BMP_RLE4) ||
                     (m_bpp == 8 && m_rle_code == BMP_RLE8))) {
                iscolor = true;
                result = true;

                if (m_bpp <= 8) {
                    memset(m_palette, 0, sizeof(m_palette));
                    m_strm.getBytes(m_palette, (clrused == 0 ? 1 << m_bpp : clrused) * 4);
                    iscolor = IsColorPalette(m_palette, m_bpp);
                } else if (m_bpp == 16 && m_rle_code == BMP_BITFIELDS) {
                    int redmask = m_strm.getDWord();
                    int greenmask = m_strm.getDWord();
                    int bluemask = m_strm.getDWord();

                    if (bluemask == 0x1f && greenmask == 0x3e0 && redmask == 0x7c00) {
                        m_bpp = 15;
                    } else if (bluemask == 0x1f && greenmask == 0x7e0 && redmask == 0xf800)
                        { ; }
                    else {
                        result = false;
                    }
                } else if (m_bpp == 16 && m_rle_code == BMP_RGB) {
                    m_bpp = 15;
                }
            }
        } else if (size == 12) {
            m_width  = m_strm.getWord();
            m_height = m_strm.getWord();
            m_bpp    = m_strm.getDWord() >> 16;
            m_rle_code = BMP_RGB;

            if (m_width > 0 && m_height > 0 &&
                    (m_bpp == 1 || m_bpp == 4 || m_bpp == 8 ||
                     m_bpp == 24 || m_bpp == 32)) {
                if (m_bpp <= 8) {
                    uchar buffer[256 * 3];
                    int j, clrused = 1 << m_bpp;
                    m_strm.getBytes(buffer, clrused * 3);
                    for (j = 0; j < clrused; j++) {
                        m_palette[j].b = buffer[3 * j + 0];
                        m_palette[j].g = buffer[3 * j + 1];
                        m_palette[j].r = buffer[3 * j + 2];
                    }
                }
                result = true;
            }
        }
    } catch (...) {
    }

    m_type = iscolor ? CV_8UC3 : CV_8UC1;
    if (!result) {
        m_offset = -1;
        m_width = m_height = -1;
        m_strm.close();
    }
    return result;
}


bool  BmpDecoder::readData(Mat& img) {
    uchar* data = img.data;
    int step = img.step;
    bool color = img.channels() > 1;
    uchar  gray_palette[256];
    bool   result = false;
    int  src_pitch = ((m_width * (m_bpp != 15 ? m_bpp : 16) + 7) / 8 + 3) & -4;
    int  nch = color ? 3 : 1;
    int  y, width3 = m_width * nch;

    if (m_offset < 0 || !m_strm.isOpened()) {
        return false;
    }

    data += (m_height - 1) * step;
    step = -step;

    AutoBuffer<uchar> _src, _bgr;
    if ((m_bpp != 24 || !color)) {
        _src.allocate(src_pitch + 32);
    }

    if (!color) {
        if (m_bpp <= 8) {
            CvtPaletteToGray(m_palette, gray_palette, 1 << m_bpp);
        }
        _bgr.allocate(m_width * 3 + 32);
    }
    uchar* src = _src, *bgr = _bgr;

    try {
        m_strm.setPos(m_offset);

        switch (m_bpp) {
            /************************* 1 BPP ************************/
        case 1:
            for (y = 0; y < m_height; y++, data += step) {
                m_strm.getBytes(src, src_pitch);
                FillColorRow1(color ? data : bgr, src, m_width, m_palette);
                if (!color) {
                    icvCvt_BGR2Gray_8u_C3C1R(bgr, 0, data, 0, cvSize(m_width, 1));
                }
            }
            result = true;
            break;

            /************************* 4 BPP ************************/
        case 4:
            if (m_rle_code == BMP_RGB) {
                for (y = 0; y < m_height; y++, data += step) {
                    m_strm.getBytes(src, src_pitch);
                    if (color) {
                        FillColorRow4(data, src, m_width, m_palette);
                    } else {
                        FillGrayRow4(data, src, m_width, gray_palette);
                    }
                }
                result = true;
            } else if (m_rle_code == BMP_RLE4) {   // rle4 compression
                uchar* line_end = data + width3;
                y = 0;

                for (;;) {
                    int code = m_strm.getWord();
                    int len = code & 255;
                    code >>= 8;
                    if (len != 0) {   // encoded mode
                        PaletteEntry clr[2];
                        uchar gray_clr[2];
                        int t = 0;

                        clr[0] = m_palette[code >> 4];
                        clr[1] = m_palette[code & 15];
                        gray_clr[0] = gray_palette[code >> 4];
                        gray_clr[1] = gray_palette[code & 15];

                        uchar* end = data + len * nch;
                        if (end > line_end) { goto decode_rle4_bad; }
                        do {
                            if (color) {
                                WRITE_PIX(data, clr[t]);
                            } else {
                                *data = gray_clr[t];
                            }
                            t ^= 1;
                        } while ((data += nch) < end);
                    } else if (code > 2) {   // absolute mode
                        if (data + code * nch > line_end) { goto decode_rle4_bad; }
                        m_strm.getBytes(src, (((code + 1) >> 1) + 1) & -2);
                        if (color) {
                            data = FillColorRow4(data, src, code, m_palette);
                        } else {
                            data = FillGrayRow4(data, src, code, gray_palette);
                        }
                    } else {
                        int x_shift3 = (int)(line_end - data);
                        int y_shift = m_height - y;

                        if (code == 2) {
                            x_shift3 = m_strm.getByte() * nch;
                            y_shift = m_strm.getByte();
                        }

                        len = x_shift3 + ((y_shift * width3) & ((code == 0) - 1));

                        if (color)
                            data = FillUniColor(data, line_end, step, width3,
                                                y, m_height, x_shift3,
                                                m_palette[0]);
                        else
                            data = FillUniGray(data, line_end, step, width3,
                                               y, m_height, x_shift3,
                                               gray_palette[0]);

                        if (y >= m_height) {
                            break;
                        }
                    }
                }

                result = true;
decode_rle4_bad: ;
            }
            break;

            /************************* 8 BPP ************************/
        case 8:
            if (m_rle_code == BMP_RGB) {
                for (y = 0; y < m_height; y++, data += step) {
                    m_strm.getBytes(src, src_pitch);
                    if (color) {
                        FillColorRow8(data, src, m_width, m_palette);
                    } else {
                        FillGrayRow8(data, src, m_width, gray_palette);
                    }
                }
                result = true;
            } else if (m_rle_code == BMP_RLE8) {   // rle8 compression
                uchar* line_end = data + width3;
                int line_end_flag = 0;
                y = 0;

                for (;;) {
                    int code = m_strm.getWord();
                    int len = code & 255;
                    code >>= 8;
                    if (len != 0) {   // encoded mode
                        int prev_y = y;
                        len *= nch;

                        if (data + len > line_end) {
                            goto decode_rle8_bad;
                        }

                        if (color)
                            data = FillUniColor(data, line_end, step, width3,
                                                y, m_height, len,
                                                m_palette[code]);
                        else
                            data = FillUniGray(data, line_end, step, width3,
                                               y, m_height, len,
                                               gray_palette[code]);

                        line_end_flag = y - prev_y;
                    } else if (code > 2) {   // absolute mode
                        int prev_y = y;
                        int code3 = code * nch;

                        if (data + code3 > line_end) {
                            goto decode_rle8_bad;
                        }
                        m_strm.getBytes(src, (code + 1) & -2);
                        if (color) {
                            data = FillColorRow8(data, src, code, m_palette);
                        } else {
                            data = FillGrayRow8(data, src, code, gray_palette);
                        }

                        line_end_flag = y - prev_y;
                    } else {
                        int x_shift3 = (int)(line_end - data);
                        int y_shift = m_height - y;

                        if (code || !line_end_flag || x_shift3 < width3) {
                            if (code == 2) {
                                x_shift3 = m_strm.getByte() * nch;
                                y_shift = m_strm.getByte();
                            }

                            x_shift3 += (y_shift * width3) & ((code == 0) - 1);

                            if (y >= m_height) {
                                break;
                            }

                            if (color)
                                data = FillUniColor(data, line_end, step, width3,
                                                    y, m_height, x_shift3,
                                                    m_palette[0]);
                            else
                                data = FillUniGray(data, line_end, step, width3,
                                                   y, m_height, x_shift3,
                                                   gray_palette[0]);

                            if (y >= m_height) {
                                break;
                            }
                        }

                        line_end_flag = 0;
                    }
                }

                result = true;
decode_rle8_bad: ;
            }
            break;
            /************************* 15 BPP ************************/
        case 15:
            for (y = 0; y < m_height; y++, data += step) {
                m_strm.getBytes(src, src_pitch);
                if (!color) {
                    icvCvt_BGR5552Gray_8u_C2C1R(src, 0, data, 0, cvSize(m_width, 1));
                } else {
                    icvCvt_BGR5552BGR_8u_C2C3R(src, 0, data, 0, cvSize(m_width, 1));
                }
            }
            result = true;
            break;
            /************************* 16 BPP ************************/
        case 16:
            for (y = 0; y < m_height; y++, data += step) {
                m_strm.getBytes(src, src_pitch);
                if (!color) {
                    icvCvt_BGR5652Gray_8u_C2C1R(src, 0, data, 0, cvSize(m_width, 1));
                } else {
                    icvCvt_BGR5652BGR_8u_C2C3R(src, 0, data, 0, cvSize(m_width, 1));
                }
            }
            result = true;
            break;
            /************************* 24 BPP ************************/
        case 24:
            for (y = 0; y < m_height; y++, data += step) {
                m_strm.getBytes(src, src_pitch);
                if (!color) {
                    icvCvt_BGR2Gray_8u_C3C1R(src, 0, data, 0, cvSize(m_width, 1));
                } else {
                    memcpy(data, src, m_width * 3);
                }
            }
            result = true;
            break;
            /************************* 32 BPP ************************/
        case 32:
            for (y = 0; y < m_height; y++, data += step) {
                m_strm.getBytes(src, src_pitch);

                if (!color) {
                    icvCvt_BGRA2Gray_8u_C4C1R(src, 0, data, 0, cvSize(m_width, 1));
                } else {
                    icvCvt_BGRA2BGR_8u_C4C3R(src, 0, data, 0, cvSize(m_width, 1));
                }
            }
            result = true;
            break;
        default:
            assert(0);
        }
    } catch (...) {
    }

    return result;
}


//////////////////////////////////////////////////////////////////////////////////////////

BmpEncoder::BmpEncoder() {
    m_description = "Windows bitmap (*.bmp;*.dib)";
    m_buf_supported = true;
}


BmpEncoder::~BmpEncoder() {
}

ImageEncoder BmpEncoder::newEncoder() const {
    return new BmpEncoder;
}

bool  BmpEncoder::write(const Mat& img, const vector<int>&) {
    int width = img.cols, height = img.rows, channels = img.channels();
    int fileStep = (width * channels + 3) & -4;
    uchar zeropad[] = "\0\0\0\0";
    WLByteStream strm;

    if (m_buf) {
        if (!strm.open(*m_buf)) {
            return false;
        }
    } else if (!strm.open(m_filename)) {
        return false;
    }

    int  bitmapHeaderSize = 40;
    int  paletteSize = channels > 1 ? 0 : 1024;
    int  headerSize = 14 /* fileheader */ + bitmapHeaderSize + paletteSize;
    int  fileSize = fileStep * height + headerSize;
    PaletteEntry palette[256];

    if (m_buf) {
        m_buf->reserve(alignSize(fileSize + 16, 256));
    }

    // write signature 'BM'
    strm.putBytes(fmtSignBmp, (int)strlen(fmtSignBmp));

    // write file header
    strm.putDWord(fileSize);   // file size
    strm.putDWord(0);
    strm.putDWord(headerSize);

    // write bitmap header
    strm.putDWord(bitmapHeaderSize);
    strm.putDWord(width);
    strm.putDWord(height);
    strm.putWord(1);
    strm.putWord(channels << 3);
    strm.putDWord(BMP_RGB);
    strm.putDWord(0);
    strm.putDWord(0);
    strm.putDWord(0);
    strm.putDWord(0);
    strm.putDWord(0);

    if (channels == 1) {
        FillGrayPalette(palette, 8);
        strm.putBytes(palette, sizeof(palette));
    }

    width *= channels;
    for (int y = height - 1; y >= 0; y--) {
        strm.putBytes(img.data + img.step * y, width);
        if (fileStep > width) {
            strm.putBytes(zeropad, fileStep - width);
        }
    }

    strm.close();
    return true;
}

}

